The present invention relates to a plasma spray method and system for high throughput screening. Particularly, the invention relates to a plasma spray method and system for selecting a thermal barrier coating.
A thermal barrier coating (TBC) is deposited onto gas turbine and other heat engine parts to reduce heat flow and to limit the operating temperature of the metal parts. To be effective, a TBC must have low thermal conductivity, strongly adhere to the part and remain adherent throughout many heating and cooling cycles. New gas turbine designs push the limits of current coating capability, particularly with regard to high temperature sintering, thermal conductivity and resistance to erosion, impact and corrosion. Hence, there is a great interest in improving thermal barrier coatings to permit operation of turbine engines at higher temperatures and to extend turbine engine part life.
Although thermal barrier coating chemistry has been extensively explored, few general principles have emerged that allow the prediction of a next generation coating material. Currently, discovery of new thermal barrier coatings depends on empirical or intuitive investigation often based on trial and error synthesis. There is a need for a method and system to investigate new thermal barrier coating candidates particularly the promising but complex multiple oxide coating candidates.
The present invention provides a method and system to rapidly investigate and screen a multiplicity of complex thermal barrier coating candidates. The method comprises selecting a thermal barrier coating by combinatorial high throughput screening (CHTS).
In another embodiment, the invention is a method of forming a CHTS array, comprising forming a solution of thermal barrier coating precursors and injecting the solution into a plasma jet of an air plasma spray (APS). The plasma jet is directed toward a substrate to deposit a gradient film formed from the precursors onto the substrate.
In another embodiment, the invention is a method, comprising steps of (i) simultaneously forming a controlled pattern of candidate TBC coatings on a substrate; and (ii) evaluating the coatings.
In still another embodiment, the invention is an APS torch system, comprising an APS torch, solution precursor vessels connected to the torch through a mixing zone and injector, a substrate oriented with respect to the torch to receive a plasma spray coating formed from solution precursors from the vessels and a controller. The controller is connected to the solution precursor vessels and the torch or substrate to control mixing of the solution precursors and to control orientation of the torch or substrate to deposit a gradient film onto the substrate from the plasma spray.
Finally in another embodiment, the invention is a CHTS array, comprising a substrate and a gradient film of candidate TBC materials deposited over the substrate.